Isochoric PVTx measurements are reported for nitrous oxide (N2O, R744A) + pentafluoroethane (CHF2CF3, R125) for both the two-phase and the superheated vapor regions at temperatures ranging from (217 to 363) K and pressures from (160 to 1853) kPa along six isochores. The data obtained in the two-phase region were used to derive vapor-liquid equilibrium (VLE) parameters using a flash method with the Carnahan-Starling-De Santis equation of state (CSD EOS). The dew point was also found for each isochore from the intersection of the P-T sequences. The dew points were then used to derive VLE parameters from CSD EOS. Results from the superheated region were compared with those predicted from the virial EOS and from the CSD EOS.